Heater



F. L. BEN EDlCT ii EATER Filed June 10, 1936.

Nov. -22, 1938.

2 Sheets-Sheet. I

- NOV. 22, 1938. F, c-r I I 2,137,224

- HEATER Filed June 10, 1936 2 Sheets-Sheet 2 Patented Nov. 22, 1938 UNITED STATES PATENT OFFICE HEATER Floyd L. Benedict, Columbus Ohio Application June 10, 1936, Serial No. 84,512 6 Claims. (01. 122-149) This invention relates to improvements in heaters and has for its primary object the provision of an improved heater so formed as to effect improved heat transfer between the gaseous heating agent and the fluid or fluids to be heated thereby,

to the general end of producing a heater, boiler or furnace which shall be efiicient in operation and simple and convenient to maintain in a clean and deposit free condition for most effective oper' ation.

Itis another object of the invention to provide a heater, boiler or furnace with improved means for effecting the circulation of the gaseous heating agent, or the hotgases incident to fuel combustion throughthe. heat circulating passages of the heater, in order that said gases may be broughtinto effective contact with the. metallic heat transferring surfaces of the heater, and to accomplish this in such manner that the fine solids, normally suspended in such heating agents may be precipitated therefrom and deposited in suitable containers, in order to prevent such solids from accumulating inthe tubular or other restricted passages of the heater intended for gas passage and heat transferrin purposes, and producing therein accumulations of solid matter which interferewith the efficient functioning of the heater. V

;A further object of the invention resides in constructing the casing of the heater and so arranging the gas conducting chambers and pas: sages of the heater asto facilitate the operation of cleaning such chambers and passages of deposits of solid matter when the need therefor is found to exist.

Other objects reside in the completion of a heater, boiler or furnace of simple, sturdyand economical construction; a heater particularly constructed for. the burningv of solid fuels with the employment of associatedautomatic stoker apparatus for delivering the fuel to the combustion space of the heater; in theprovision of a heater which may be serviced in a cleanly manner without producing dust and dirt exteriorly of the same; a heaterhaving a novel arrangement of gas circulatingpassages for the gaseous products of combustion, the saidpassages being so designed and relatively arranged as to effect an eflicient heat transfer between the products of combustion, the confiningwalls of the passages and the fluids to be heated disposed around said walls, to the end of obtaining low temperatures on- .the partof said products of combustion when thelatterare delivered to the outlet stack of the heater; in the provision of means for conveniently removing dust, carbon and fly ash deposit from the deposit collecting chambers of the heater; and various other improved features of construction and operation which will be in part obvious and in part pointed out hereinafter.

In the accompanying drawings, forming apart of the specification, in which similar characters of reference denote like and corresponding parts throughout the several views thereof:

Fig. 1 is a view in front elevation of a heater constructed in accordance with the present invention;

Fig. 2 is a side elevation of the casing of the heater; I

Fig. 3 is a vertical longitudinal sectional view taken throughthe heater on the plane indicated by the line IIIIII of Fig. 1;

Fig. 4 is a similar view on the offset or staggered planes indicated by the lines IV-IV of Fig. 1;

Fig. 5 is a vertical transverse sectional view of the heater on the plane indicated by the line V--V of Fig.4;

Fig. 6 is a similar view on the plane denoted by the. line VI-VI of Fig. 4;

Fig. '7 is a horizontal sectional View on the plane indicated by the line VII-VII of Fig. 4.

In the single embodiment of my improved heater illustrated in the drawings, the numeral I designates the casing of the heater. In this instance, the casing is formed to include spaced vertical side walls 22, a crowned top wall 3 and front and back walls 4 and 5 respectively. These walls may be formed from metallic sheeting or castings and of any suitable size and mechanical strength, depending upon the practical uses to which the heater is adapted to be placed and the thermal requirements therefor. It will be understood that the casing may be provided with suitable exterior layers of insulation, not shown, to reduce heat losses "in accordance with accepted heater practice.

Arranged within the outer casing I andsuitably supported in connection with the walls of the latter is an internal casing 6 which, in the embodiment of the invention illustrated, also includes spaced vertical side walls l--|, a crowned top 8 and vertically arranged front and back walls 9 and II] respectively. The walls ofthe inner casing 6 are inwardly spaced from the corresponding walls of the outer casing. The inner casing is formed, in this instance, with a bottom H in which is provided a retort l2. A conveyor screw I3 is disclosed in the bottom of the retort for the purpose of conducting solid fuel from anexteriorly disposed fuel storage space or hopper into the retort. It will be understood, however, that other types of fuel, either solid or fluid, may be burned in the combustion space I4 provided within the confines of the casing 6 above the bottom I I thereof and that I do not confine the present invention to the burning of any particular fuel or any specific means for effecting the introduction thereof into the heater. Below the bottom II, there is provided an air chamber I5 by which air may be introduced, preferably under a positive pressure, into the upper end of the retort by way of the restricted ports I6, air en--- tering the chamber I5 through the conduit or opening disclosed at II. The combustion chamber or space I4 is rendered accessible by means of registering openings I8 formed in the front walls 4 and 9 of said casings, a door I9 being hingedly mounted on the front wall 4 of the casing I to normally close the openings I8 and the combustion chamber. It will be noted that the combustion chamber I4 is of liberal size and ofample cubical capacity in providing for complete combustion of the fuels introduced therein in order to effectively impart heat to the metallic sheets or walls of the inner casing and thence to the fluid medium to be heated. In this instance, the said fluid medium may be assumed to be water and is arranged in the inverted substantially U-shaped chamber 20 formed between the inner and outer casings. It will be obvious to those skilled in the art that fluids other than water, either gaseous or liquid,.may be heated in'the spaces indicated by the chamber 20.

At the rear of the combustion chamber I4, there is arranged a hollow, upstanding bridge wall 2|, which is spaced from the vertical back wall ID of the inner casing to provide a vertical chamber 22 therebetween through which the products of combustion, passing from the combustion space I4 travels in a generally downward direction. In the bottom of the chamber 22, there is arranged a removable container 23 which is adapted to receive precipitated'solid matter, such as ash, carbon or soot, which has been carried over into the chamber 22 through entrainment with the gaseous products of combustion. The precipitation of this undesired solid matter is facilitated by the change in direction of movement of the combustion gases after passing upwardly through the space I4, thence over the open top of the bridge wall 2I and down wardly through the chamber 22.

Communicating with the opposite sides of the chamber 22 are vertical banks of primary heating tubes 24. These tubes are disposed in parallel horizontal order and are located in the lower portions of the chamber 20, being surrounded by the fluid undergoing heating. The gases of combustion after entering the vertical chamber 22 to the rear of the bridge wall 2|, spread laterally and downwardly and enter the rear open ends of-the tubes 24,'a large proportion of the undesired solid matter present in such gases having been precipitated and deposited in' the container 23 by the rapid change in the direction of flow of the gaseous products of combustion, so that the latter, when entering the tubes 24, will be in a fairly clean state and deprived of a large proportion of their normally solid content. This is done in order to minimize the deposition of carbon, soot and ash in the relatively restricted passages afforded by the tubes 24.

After enteringthe tubes 24, the gases of combustion travel forwardly and longitudinally therethrough giving up a large part of their heat to the walls of said tubes and thence to the fluid medium surrounding the tubes. The heated gases upon emerging from the forward ends of the tubes 24 are delivered into vertical .conduits 25 arranged in the forward corner portions of the casing I, as shown in Fig. 7. The bottoms of these conduits are equipped with removable containers 26 for the retention and entrapment of unburned fuel'solids carried in entrainment with the gaseous products of combustion following the passage of the latter through the primary tubes 24.

It will be understood that these ash receivers or containers indicated at 23 and 26, may be conveniently removed from time to time from their operating positions within the heater in order to maintain the latter internally free from such objectionable and efliciency retarding products.

It is also within the scope of the invention to utilize means for continuously removing ash deposit from the bottom of the chamber 22 and/or the conduits 25, as well as through the intermittent means here disclosed.

As indicated by the arrows in Fig. 4, the heating gases, upon emerging from the forward ends of the primary bank of tubes 24, pass upwardly through the conduits 25, precipitating their ash content to a large degree into the containers 26, and then enter the forward ends of a bank of larger diametered secondary tubes 21. These tubes are also arranged in the chamber 28 and are surrounded by the fluid medium undergoing heating. The gases of combustion pass longitudinally through the tubes 21 in the opposite direction to the flow thereof through the primary tubes 24, and upon emerging from the tubes 21 are delivered into a tertiary purging chamber 28 arranged at the rear of the casing I. The solid matter present in the gases dis-" charged into the duct 28 is usually precipitated to the bottom of said duct and may be removed through the normally closed outlet opening 29 therein. The duct in the upper region thereof includes a horizontal branch 30 which leads to the outlet stack, not shown, for the heater gases.

In alignment with the rear ends of the secondary tubes 21, the back wall of the duct 28 is equipped with closures 3| by which access to the tubes 21 for cleaning purposes is afforded. Also, the front wall 4 of the casing I in alignment with the forward ends of the primary and secondary tubes 24 and 21 respetcively, is provided with a plurality of removable cover plates or doors 33 which may be opened or removed to permit of convenient access to said tubes for cleaning and the removal of internally obstructing deposit which may collect after prolonged periods of operation. Likewise, the back wall 5 of the casing I is provided with removable cover plates or doors 33 for openings in said wall to obtain convenient access to the rear ends of the primary tubes 24.

in which the fuel is burned, the said compartment being of such proportions asto afford a large area for the fuel bed, with sufficient height above the'fuel bed to provide a greater volume and extended time for the complete combustion of the combustibles emanating from the fuel bed. The large volume and greater height of the combustion chamber retards the time from the periodthe combustibles leave the fuel bed until they come into contact with the surrounding confining surfaces,'which tends to prevent premature cooling of the combustible mixtures below the ignition temperatures before combustion is completed As the air which supplies oxygen to support combustion passes through the burning fuel bed and mixes with the gases emanating from the fuel, there must be a certain rate of speed at whichthe gaseous mixture passes through and leaves the fuel bed. With'most solid fuel, this velocity of the gaseous mixture is sufficient to entrain a certain amount of unburned solid matter which floats along in the path of the flowing gases from the fuel bed. This unburned solid matter may comprise unconsumed particles of fuel or such residues as carbon, soot or ash, which solids are generally termed fly ash.

Through the above described construction of the heater, this fly ash is readily trapped and may be conveniently removed from time to time so that the heat transmitting surfaces may be kept in a clean state and devoid of. solid deposits which retard the rate of heat transmission.

The present invention therefore provides for complete combustion, within practical limits, of the fuels consumed within the combustion chamber, effective heat transfer between the resulting gases of combustion and the fluid medium to be heated thereby, the removal of solids from the gases of combustion which so frequently clog the flues of such a heater or produce deposits which interfere with heat transmission through the walls of the tubes, and a heater which will be clean and easy tomaintain in its most efficient working condition.

When a fuel bed is established in the bottom of the combustion chamber M, the construction of the furnace is such as to facilitate the removal of clinkers, ash, etc., without removing the latter through the room or atmosphere surrounding the exterior of the furnace, by providing the front of the combustion chamber with a short upstanding wall 40, located in alignment with the door 19 and the opening l8. Clinkers removed over the wall 4!! may be dropped directly into the container 26 through the opening 4|, as shown in Fig. 3, thereby avoiding ash deposit in the surrounding room area, since when the door I9 is opened to permit of this operation, the draft therethrough is in an inward direction.

While I have described what I consider to be the preferred form of my invention, nevertheless it will be understood by those skilled in the art that the same is subject to considerable change and modification without departing from the essential features of the invention, as the latter have been defined in the following claims.

What is claimed is:

1. In a heater, inner and outer casings having spaced walls providing a heating chamber therebetween, the interior of said inner casing being formed to provide a combustion chamber, a bridge wall disposed within said inner casing and producing at the rear of said inner easing a purging chamber through which the products of combustion discharged from said combustion chamber pass substantially downward, secondary vertically arranged purging chambers at the front of said heater located between the inner and outer casings, a primary bank of open ended flues uniting the primary and secondary purging chambers, and a secondary bank of flues disposed above the primary bank and uniting the secondary chambers with a tertiary chamber disposed at the rear of the heater, said primary and secondary flues being disposed in said heating chamber for intimate engagement with the fiuid to be heated.

2. In a heater, inner, and outer casings, the complemental walls of said casings being relatively spaced to provide a heating chamber therebetween for the reception of a fluid to be heated, the interior of said inner casing being formed to provide a combustion chamber, a bridge wall disposed within said inner casing and spaced from the rear wall thereof to produce a primary purging chamber for the substantially downward passage of products of combustion discharged from the upper part of said combustion chamber, secondary vertically arranged purging chambers at the front of said heater, open ended primary flues arranged in spaced vertical order at the sides of said primary purging chamber and extending through said heating chamber for conducting gaseous products of combustion from the primary purging chamber to the secondary purging chambers, a tertiary purging chamber arranged at the rear of said heater and provided with a waste gas outlet, and a plurality of secondary flues arranged above the primary flues in said heating chamber and uniting for gas flow the secondary chambers with said tertiary chamber.

3. In a'heater, inner and outer casings, the

complemental walls of said casings being relatively spaced to provide a heating chamber therebetween for the reception of a fluid to be heated, the interior of said inner casing being formed to provide a combustion chamber, a bridge wall disposed within said inner casing and spaced from the rear wall thereof to produce a primary purging chamber forthe substantially downward passage of products of combustion discharged from the upper part of said combustion chamber, secondary vertically arranged purging chambers at the front of said heater, open ended primary flues arranged in spaced vertical order at the sides of said primary purging chamber and extending through said heating chamber for conducting gaseous products of combustion from the primary purging chamber to the secondary purging chambers, a tertiary purging chamber arranged at the rear of said heater and provided with a waste gas outlet, a plurality of secondary flues arranged above the primary flues in said heating chamber and uniting for gas flow the secondary chambers with said tertiary chamber, and traps disposed in I the bottoms of said primary, secondary and tertiary purging chambers for the reception of solids precipitated from the combustion gases delivered to said last-named chambers.

4. In a heater, inner and outer casings, the complemental walls of said casings being relatively spaced to provide a heating chamber therebetween for the reception of a fluid to be heated, the interior of said inner casing being formed to provide a combustion chamber, a bridge wall disposed within said inner casing and spaced from the rear wall thereof to produce a primary purging chamber for the substantially downward passage of products of combustion discharged from the upper part of said combustion chamber, secondary vertically arranged purging chambers at the front of said heater, open ended primary fiues arranged in spaced vertical order at the sides of said primary purging chamber and extending through said heating chamber for conducting gaseous products of combustion from the primary purging chamber to the secondary purging chambers, a tertiary purging chamber arranged at the rear of said heater and provided with a waste gas outlet, a plurality of secondary flues arranged above the primary fiues in said heating chamber and uniting for gas flow the secondary chambers with said tertiary chamber, traps disposed in the bottoms of said primary, secondary and tertiary purging chambers for the reception of solids precipitated-from the combustion gases delivered to said last-named chambers, and means for removing the trapped solids from said heater.

5. In a heater of the class described, inner and outer casings having spaced walls providing a heating chamber therebetween, the interior of said inner casing being formed to provide a combustion chamber, a bridge wall disposed vertically within said inner casing and producing at the rear of the latter a primary purging chamber through which the products of combustion discharged from said combustion chamber pass downwardly and laterally, said casings being formed at the front of said heater to provide a secondary vertically arranged purging chamber, a primary bank of open-ended flues uniting the primary and secondary purging chambers, and a secondary bank of fiues arranged above the primary bank and uniting the secondary chamber with the tertiary chamber disposed at the rear of the heater, said secondary fiues being of greater length than the primary fiues to extend over the top of said primary chamber.

'6. The structure as specified in claim 5 and further characterized by having the individual flues of the secondary bank of greater diameter than the individual flues comprising the primary bank.

FLOYD L. BENEDICT. 

